The pulse is the rhythmic expansion and contraction of an artery wall, which occurs as blood is forcefully ejected from the heart with each beat. This pressure wave travels throughout the arterial system, allowing the heart’s performance to be monitored externally. Checking a pulse provides immediate, non-invasive feedback on circulatory function and heart rate. The carotid pulse is one of the body’s most reliable sites for assessment, as its strength and accessibility make it a primary indicator of effective cardiac output.
Anatomical Location and Function
The carotid pulse originates from the two common carotid arteries, which ascend through the neck on either side of the trachea. These large vessels deliver the majority of oxygenated blood directly to the brain, face, and head structures. They ensure the continuous perfusion of the central nervous system, which requires a constant and robust blood supply.
The arteries are relatively superficial, running close to the skin’s surface within the neck. They are found in the soft groove between the larynx (voice box) and the sternocleidomastoid muscle. Because the common carotid artery is a major conduit of blood flow, the pressure wave is robust at this site. This makes the pulse easily felt, even when the heart’s pumping action is too weak to register in smaller, more distant arteries.
Proper Technique for Checking the Pulse
To accurately locate the carotid pulse, first position the index and middle fingers on the larynx. From this central point, gently slide the two fingers laterally into the soft depression on either side of the neck. Use these two fingers together, avoiding the thumb, which has its own noticeable pulse that can lead to miscounting the rate.
Once the rhythmic throbbing is felt, apply only light pressure to avoid compressing the artery and restricting blood flow. The pulse rate is measured by counting the beats felt over a specific duration to establish the beats per minute (BPM). A common method is to count the beats that occur within 15 seconds and then multiply that number by four.
Never attempt to check both carotid arteries simultaneously. Compressing both vessels severely restricts the flow of oxygen-rich blood to the brain, potentially leading to dizziness, fainting, or serious complications.
Importance in Emergency Situations
The accessibility and consistent strength of the carotid pulse make it the standard location for assessing circulation during emergency situations. In protocols like Cardiopulmonary Resuscitation (CPR), checking the carotid pulse is the fastest way for a first responder to determine if the heart is generating effective output. When a person is in shock or has suffered severe blood loss, peripheral pulses (like the radial pulse) may become too faint to detect as the body diverts blood flow away from the extremities.
The carotid pulse remains palpable even when blood pressure is significantly low because it is closer to the heart and supplies the brain. The absence of a discernible carotid pulse indicates that the heart has stopped pumping effectively. Recognizing this absence prompts the immediate initiation of chest compressions to manually circulate blood until medical help arrives.